Abstract: An aqueous epoxy resin system ABC comprising an aqueously dispersed epoxy resin A having, on the average, at least one epoxy group per molecule, a water-soluble or water-dispersible curing agent B which comprises the reaction product of an amine B1 having at least one primary and at least one secondary amino group, and an adduct B2 of a polyalkylene ether polyol B21 and an opexide component B22, and aminoplast compound C having a mass fraction of at least 0.1% of sulphonate or sulphonic acid groups, a coating composition ABCD for thick layer applications comprising the aqueous epoxy resin system ABC and at least one particulate filler D selected from the group consisting of talc, mica, quartz, titanium dioxide, aluminium dioxide, calcium carbonate, and dolomite, and a process for coating mineral or concrete based substrates or floors with such coating compositions.